Conventionally, a vehicle such as a hybrid vehicle, an electric vehicle and a fuel-cell vehicle using an electric motor as a driving source has been known. Such a vehicle is provided with a power storage mechanism such as a battery for storing electric power supplied to the electric motor. The electric power generated during regenerative braking or generated by a power generator mounted in the vehicle is stored in the battery.
There are also some vehicles in which electric power is supplied from a power supply external to the vehicle such as a household power supply to the battery mounted in the vehicle for charging the battery. The outlet disposed in the house is coupled to the connector provided in the vehicle via a cable to supply electric power from the household power supply to the battery of the vehicle. The vehicle having a battery mounted therein and charged by the power supply provided external to the vehicle is hereinafter also referred to as a plug-in vehicle.
When a malfunction occurs in the charging system for controlling the charging power during battery charging, the battery cannot be normally charged. However, it is difficult for the user to detect the malfunction of the charging system, which requires the charging system itself to determine whether or not a malfunction occurs therein.
Japanese Patent Laying-Open No. 11-205909 (Patent Document 1) discloses a charging device for an electric vehicle for checking the operation of the ground fault interrupter when the electric vehicle is charged. The charging device for an electric vehicle disclosed in Patent Document 1 serves as a charging device for charging a battery of an electric vehicle using an external power supply, the electric vehicle including the battery, an inverter connected to the battery and an alternating-current (AC) motor connected to the inverter. The charging device for an electric vehicle includes a charging relay connecting the electric vehicle and the external power supply, a ground fault interrupter provided between the charging relay and the external power supply, and a control unit for controlling opening and closing of the charging relay. The ground fault interrupter includes a detector for detecting a short circuit of a charging circuit, a ground fault relay interrupting the charging circuit when the detector detects a short circuit, a short-circuit unit for forcefully short-circuiting the charging circuit prior to the closing operation of the charging relay. The control unit prevents the closing operation of the charging relay in the case where the ground fault relay is not interrupted even when the charging circuit is short-circuited by the short-circuit means.
According to the charging device disclosed in this document, even when the charging circuit is forcefully short-circuited prior to the charging operation, the ground fault relay is not interrupted and thus the charging circuit cannot be interrupted, in which case charging is prevented. Consequently, the charging operation can be smoothly carried out.
Furthermore, according to the disclosure in Japanese Patent Laying-Open No. 11-205909, when the electric vehicle is shifted to a charging mode, the ground fault relay is first controlled to be closed to connect an outlet to a connector on the vehicle side, and then, it is examined whether the ground fault interrupter is normally operated.    Patent Document 1: Japanese Patent Laying-Open No. 11-205909